Apologies if it seems confusing to you.
I think it would be tricky to code an auto-target mechanic and I don't think the card really needs it. You could just the card the buff ability costing 4
.
The unupped seems UP. +1 in max stats is not very much (best use I would see is with Gravity Pull/Acceleration, and that combos better with Guardian Angel and BB)
The upped doesn't seem to reasonable fit Other. If you are making the upgraded card Other for accessbility I would just make the cost Other and switch the ability cost back to Life. (There should be an option in the card maker that allows you to remove the cost icon on an elemental card and make it cost Other.)
Overall I think it should have an ability cost of 1-3
, in comparison to Guardian Angel.
And welcome to Card Ideas and Art!